Best Time to Fly PHL to SEA: On-Time Stats by Hour & Airline
Philadelphia International → Seattle/Tacoma International
Data through July 2026 · Last updated October 18, 2026
1,388 flights were scheduled from Philadelphia (PHL) to Seattle (SEA) in the last 12 months, and 70.1% of those that flew arrived on time, 7.5 points below the US average of 77.6%.
American Airlines was the most punctual of the 3 airlines on the route at 72.1%, while Alaska Airlines trailed at 68.3%.
February has been the best month (82% on time) and Thursday the weakest day of the week (64%).
1.8% of flights were cancelled, versus 1.8% nationally.
PHL to SEA on-time performance by airline
Last 12 months. Airlines with fewer than 30 completed flights are marked “limited data”.
| Airline | On time | Avg delay when late | Cancelled | Flights |
|---|---|---|---|---|
| American Airlines | 72.1% | 51 min | 2.2% | 649 |
| Delta Air Lines | 69.1% | 77 min | 0.0% | 82 |
| Alaska Airlines | 68.3% | 50 min | 1.7% | 657 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly PHL to SEA
On-time arrival % by scheduled departure hour (local time), 2,400 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 6am–7am | 70.6% | 1.4% | 69 |
| 7am–8am | 75.6% | 0.4% | 559 |
| 8am–9am | 80.5% | 0.8% | 264 |
| 9am–10am | 93.9% | 0.0% | 33 |
| 10am–11am | Limited data | 2 | |
| 4pm–5pm | 74.6% | 5.6% | 71 |
| 5pm–6pm | 88.2% | 0.0% | 34 |
| 6pm–7pm | 61.2% | 1.9% | 1,053 |
| 7pm–8pm | 62.2% | 3.5% | 315 |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on PHL to SEA
On-time arrivals during holiday periods compared with all other days, last 24 months.
| Period | On time | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | 65.7% | -5.9 pts | 0.0% | 35 |
| Christmas & New Year (Dec 20 - Jan 3) | 58.0% | -13.7 pts | 1.1% | 89 |
| Summer peak (Jun 15 - Aug 15) | 60.9% | -10.7 pts | 2.5% | 591 |
| All other days | 71.6% | — | 1.4% | 1,685 |
Monthly on-time trend
On-time arrival % each month, with the 12-month US average for reference.
What causes delays on this route
Share of reported delay minutes, last 12 months (BTS cause categories).